System and method for enhanced sealing of well tubulars

ABSTRACT

A well isolation includes a radially expandable sealing element that engages an interior wall of the wellbore tubular and a radially expandable expansion cone in telescopic relationship with the sealing element. The expansion cone expands the sealing element and a swage telescopically engages and expands the expansion cone.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application Ser.No. 61/601,339 filed Feb. 21, 2012 the entire disclosure of which isincorporated herein by reference in its entirety.

BACKGROUND OF THE DISCLOSURE

1. Field of Disclosure

The present disclosure relates to devices and methods for isolating oneor more selected zones in a wellbore.

2. Description of the Related Art

In the oil and gas industry, a well is drilled to a subterraneanhydrocarbon reservoir. A casing string is then run into the well, andthe casing string is cemented into place. The casing string can then beperforated and the well completed to the reservoir. A production stringmay be concentrically placed within the casing string. During thedrilling, completion, and production phase, operators find it necessaryto perform various remedial work, repair and maintenance to the well,casing string, and production string. For instance, holes may be createdin the tubular member accidentally or intentionally. Alternatively,operators may find it beneficial to isolate certain zones. Regardless ofthe specific application, it is necessary to place certain downholeassemblies such as a liner patch within the tubular member, and in turn,anchor and seal the down hole assemblies within the tubular member.

Numerous devices have been attempted to create a seal and anchor forthese downhole assemblies. For instance, U.S. Pat. No. 3,948,321entitled “LINER AND REINFORCING SWAGE FOR CONDUIT IN A WELLBORE ANDMETHOD AND APPARATUS FOR SETTING SAME” to Owen et al, discloses a methodand apparatus for emplacing a liner in a conduit with the use of swagemeans and a setting tool. The Owen et al disclosure anchors and sealsthe liner within the wellbore.

While conventional wellbore sealing devices have generally beenadequate, situations may arise wherein such conventional sealing devicescannot be efficiently employed. For instance, an inner diameter of awell tubular may complicate the insertion of conventional sealingdevices. In aspects, the present disclosure addresses these and otherdrawbacks of the prior art.

SUMMARY OF THE DISCLOSURE

In aspects, the present disclosure provides a well isolation apparatusfor use in a wellbore. The apparatus may include a radially expandablesealing element configured to engage an interior wall of the wellboretubular; a radially expandable expansion cone in telescopic relationshipwith the sealing element, the expansion cone being configured to expandthe sealing element; and a swage configured to telescopically engage andexpand the expansion cone.

The above-recited examples of features of the disclosure have beensummarized rather broadly in order that the detailed description thereofthat follows may be better understood, and in order that thecontributions to the art may be appreciated. There are, of course,additional features of the disclosure that will be described hereinafterand which will form the subject of the claims appended hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

For detailed understanding of the present disclosure, references shouldbe made to the following detailed description of the preferredembodiment, taken in conjunction with the accompanying drawings, inwhich like elements have been given like numerals and wherein:

FIG. 1 is a schematic sectional view of one embodiment of an apparatusof the present disclosure as positioned within a wellbore intersecting asubterranean formation;

FIGS. 2A-C illustrate one embodiment of a well isolator in accordancewith the present disclosure in various stages of installation; and

FIGS. 3A-C illustrate one embodiment of a well isolation system inaccordance with the present disclosure for deploying the FIGS. 2A-C wellisolator.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present disclosure relates to devices and methods for anchoring oneor more downhole tools and/or isolating a section of a wellbore. Thepresent disclosure is susceptible to embodiments of different forms.There are shown in the drawings, and herein will be described in detail,specific embodiments of the present disclosure with the understandingthat the present disclosure is to be considered an exemplification ofthe principles of the disclosure, and is not intended to limit thedisclosure to that illustrated and described herein.

Referring now to FIG. 1, there is shown a well having wellbore 10 formedin a subterranean formation 12. The well may be horizontal,multi-lateral, slim hole, monobore or geothermal. The wellbore 10includes a casing 14 that may be cemented in place. At the surface, awell head 16 and associated equipment are positioned over the wellbore10. As is known, production fluids such as oil and gas flow up thewellbore 10 to the surface. In some situations, a zone 18 in thewellbore 10 may require isolation to prevent wellbore fluids such asdrilling fluid invading a production zone, formation fluids (e.g.,water) from entering the wellbore 10, and/or to stabilize wellboretubulars. Such undesirable fluid flow or tubular instability can arisedue to discontinuities 20 (e.g., human made perforations, corrosion,etc.). In some instances, conveying remediation tools to the zone 18 maybe complicated by one or more reduced diameter sections 22 that limitthe outer diameter of tools that can be conveyed to the zone 18.

Embodiments of the present disclosure include a diametrically compactwell isolation system 26 that may be used to provide long-termisolation/strength at perforations, splits, corrosion and/or leaks inwellbore tubulars (e.g., casing, liner, production tubing, etc.) in suchsituations. The well isolation system 26 may include an isolator 30 thatis activated by a setting tool 28. The well isolation system 26 may betripped into the wellbore via a suitable conveyance device 29 (e.g.,electric/wire line, slick line, tubing, drill pipe or coil tubing).

The setting tool 28 may be a known device that generates axial loadings.The setting tool 28 may be energized using electrical power, pressurizedfluid, energetic material, or any other known method. As will bedescribed in greater detail below, the wellbore isolation system 26 maybe sized to pass through downhole restrictions, but have a range ofdiametrical expansion that enables engagement with an internal diameterof a casing 14 or other downhole well tubular. Additionally, thewellbore isolation system 26 may utilize multiple expanding componentsto provide a progressively stacked sealing assembly.

Referring now to FIGS. 2A-C, there is shown in greater detail oneembodiment of a wellbore isolator 30 that may be used to isolate adesired section of a well. FIG. 2A depicts the isolator 30 when runningin hole and prior to setting. The isolator 30 may include a swage 32that is a non-deforming tubular component with a tapered end 34, anexpansion cone 36 that is a deformable element with a tapered end 38,and a sealing element 40 that is a deformable element that engages andseals against an internal surface of a wellbore tubular. The expansioncone 36 and the sealing element 40 may have flared ends for receiving anadjacent element. In one sense, the swage 32, the expansion cone 36, andthe sealing element 40 may be serially aligned tubular members thattelescopically engage one another. By telescopically, it is meant thatone tube slides into a bore of an adjacent tube.

The sealing element 40 may include a seal section 42 that is configuredto anchor and/or seal against a desired well tubular surface. The sealsection 42 may include circumferential ribs, o-rings, or other featuresto provide a suitable fluid tight (e.g., liquid tight or gas tight)seal. The sealing element 40 may also include a connector end 44 shapedto receive or connect with additional elements (e.g., a profile sub 90of FIG. 3A).

Referring now to FIG. 2B, the swage 32 is shown after being axiallydriven into flared end of the expansion cone 36 and before expansion ofthe sealing element 40. Because the swage 32 is made of a material thatis harder or more rigid than that of the expansion cone 36, an outersurface 52 of the expansion cone 36 expands diametrically outward from afirst diameter (shown in FIG. 2A) to a larger second diameter.

Referring now to FIG. 2C, the swage 32 and the expansion cone 36 areshown after being axially driven into the sealing element 40. Becausethe swage 32 is also made of a material that is harder or more rigidthat that of the sealing element 40, an outer surface 54 of the sealsection 42 expands also diametrically outward from a first diameter(shown in FIG. 2B) to a larger second diameter. The expansion cone 36may also be formed of a material that is harder or more rigid than thatof the sealing element 40.

It should be appreciated that the expanded diameter of the sealingelement 40 is larger than that obtainable by inserting only the swage 32or the expansion cone 36 into the sealing element 40. That is, thecombined radial thicknesses of the swage 32 and expansion cone 36 allowthe sealing element 40 to be expanded to an outer diameter larger thanthat otherwise achievable. Advantageously, the combined radial thicknessof the swage 32 and expansion cone 36 only occurs after the isolator 30has already passed through the reduced diameter section 22 shown in FIG.1.

Referring now to FIGS. 1 and 3A-C, there are shown further aspects ofthe wellbore sealing system 26. The wellbore isolation system 26 mayinclude an actuator assembly 60 that causes a sequential engagementbetween the swage 32, expansion cone 36, and the sealing element 40 ofthe isolator 30. The actuator assembly 60 may be operated using thesetting tool 28 (FIG. 1). By sequential, it is meant that the start ofeach engagement that causes radial expansion is staggered in time.

In one embodiment, the actuator assembly 60 may include a timing rod 62,a release sleeve 64, an upper locking member 66, a lower locking member68, a compression sleeve 70, and a profile sub 72. The timing rod 62 maybe a rigid elongated element that is telescopically received into thetube-shaped release sleeve 64. The timing rod 62 is connected to thesetting tool 28 (FIG. 1) such that the timing rod 62 may be pulledupward, or more generally, in a direction opposite to the movement ofthe swage 32. The release sleeve 64 may include an enlarged outerdiameter portion 74 that maintains the upper locking member 66 in anengaged position and a smaller diameter necked portion 76 that allowsthe upper locking member 66 to radially retract into a disengagedposition.

The locking members 66, 68 and the compression sleeve 70 cooperate totransfer axial loadings from the expansion cone 36 to the profile sub72. The profile sub 72 may be connected to the sealing element 40 via asuitable connection, such as mating threads 78. In one arrangement, thelocking members 66, 68 may be collets or other selectively anchoringdevices that can extend and retract radially. The upper locking member66 may be positioned to engage a suitable recess 80 in the expansioncone 36 and the lower locking member 68 may be positioned to engage arecess 82 in the profile sub 72. The compression sleeve 70 is nestedbetween the upper and lower locking members 66, 68.

During the initial phase of installation, the axial loading caused bythe swage 32 entering the expansion cone 36 is transferred to the upperlocking member 66. The upper locking member 66 transmits the loading tothe compression sleeve 70, which then axially loads the lower lockingmember 68. The lower locking member 68 transfers the load to the profilesub 72. Thus, the axial loading caused by the swage 32 is not initiallyapplied to the sealing element 40.

An exemplary operation of the wellbore sealing system 30 will bediscussed with reference to FIGS. 1, 3A-C. The wellbore sealing system26 may be positioned at the selected location 18 in the wellbore 10using the conveyance device 29. It should be appreciated that therelatively small cross-sectional profile of the unassembled wellboreisolation system 26 allows passage through bore restrictions 22. Onceproperly positioned, the setting tool 28 is activated by a suitablepower source (e.g., pressurized fluid, electricity, energetic material,etc.) to drive the swage 32 into the expansion cone 36. The upperlocking member 66 keeps the expansion cone 36 stationary by transferringthe axial loading caused by the swage 32 to the profile sub 72 via thecompression sleeve 70 and the lower locking member 68. As the swage 32slides into the expansion cone 36, the expansion cone 36 increases indiametrical size.

While the setting tool 28 is driving the swage 32 into the expansioncone 36, the setting tool 28 is also pulling the timing rod 62 upward orin an axial direction opposite to that of the swage 32. The timing rod62 includes a shoulder 86 at a lower end 88 that can interferinglyengage an end 89 of the release sleeve 64. Upon engagement, the timingrod 62 pushes the release sleeve 64 axially upward. The axialtranslation of the release sleeve 64 slides the enlarged outer diameterportion 74 out from under the upper locking member 66. Soon thereafter,the necked portion 76 slides under the upper locking member 66 andallows the upper locking member 66 to retract into the necked portion76. Thus, the expansion cone 36 is released and free to slide into theseal section 42 of the sealing element 40.

The stroke speed of timing rod 62 is selected to provide a travel timesufficient to allow the swage 32 to substantially telescopically engagea substantial section of the expansion cone 36. That is, the speed isselected such that the travel time needed for the shoulder 86 to contactthe release sleeve 64 and the travel time needed for the necked portion76 to slide under the upper locking member 66 is sufficient to allow theswage 32 to expand the expansion cone 36 to a functionally effectivestate. Specifically, the swage 32 expands enough of the expansion cone36 such that subsequent engagement with the seal section 42 allows theseal element 40 to have a desired seal engagement with an adjacentsurface. Thus, the swage 32, the expansion cone 36, and the sealingelement 40 have translated from an axially, serially aligned arrangementto a primarily concentrically aligned compacted arrangement.

Referring now to FIG. 3C, the swage 32 and the expansion cone 36 areshown in an installed position within the sealing element 40. Thesealing element 40 has been expanded radially outward into sealingengagement with an adjacent surface (not shown). As can be seen, thesetting tool 28 has axially compressed the isolator 30 to a concentricalignment of swage 32, the expansion cone 36, and the sealing element 40at the seal formed between the sealing element and an adjacent surfacein the wellbore.

To complete the installation, the setting tool 28 continues to pull thetiming rod 62 upward until contact is made with a release ring 90. Arelease ring 90 may be an annular member that is configured to retractthe lower locking member 68. The release ring 90 is disposed uphole ofan enlarged head 92 of the timing rod 62 and is shaped to engage andretract the lower locking member 68. As the timing rod 62 travelsupward, the enlarged head 92 engages and drives the release ring 90axially into the lower locking member 68. The pressure applied by therelease ring 90 retracts the lower locking member 68 to disengage fromthe profile sub 72. The upper locking member 66 has already beenretracted. At this point, further upward movement of the timing rod 62lifts the components internal to the well isolator 30 upward. At theappropriate time, the setting tool and these internal elements may beretrieved to the surface using the conveyance device 29 or some othersuitable means.

As use throughout, the term “radially expandable” or “diametrically”expandable means that the expansion is an engineered attribute that isexpressly intended to perform a specific function. As discussed above,the function may be to induce a compressive sealing engagement.

It should be understood that the devices according to the presentdisclosure are susceptible to various embodiments. For example,Referring to FIG. 3A, in certain embodiments, a support sleeve 95 may beused to strengthen one or more sections of the isolator 30. The sleeve95 may be a tubular member that is flexible enough to diametricallyexpand while at the same time applying a compressive force sufficient toreduce buckling, rupture, or other type of failure of the underlyingstructure. It should be understood that a sleeve is merely illustrativeof support elements that may be used to reinforce one more more sectionsof the isolator 30. Other support elements, include, but are not limitedto, bands, rings, clamps, etc.

The foregoing description is directed to particular embodiments of thepresent disclosure for the purpose of illustration and explanation. Itwill be apparent, however, to one skilled in the art that manymodifications and changes to the embodiment set forth above are possiblewithout departing from the scope of the disclosure. Thus, it is intendedthat the following claims be interpreted to embrace all suchmodifications and changes.

1. A well isolation apparatus for use in a wellbore, comprising: anisolator conveyed into the wellbore by a conveyance device, the isolatorincluding a swage, an expansion cone, and a sealing element insubstantially serial alignment; an actuator configured to sequentiallyengage the swage, expansion cone, and the sealing element; and a settingtool configured to axially compress the isolator to a concentricalignment of the swage, the expansion cone, and the sealing element at aseal formed between the sealing element and an adjacent surface in thewellbore.
 2. The well isolation apparatus according to claim 1, wherein:the sealing element is a radially expandable tubular having a sealsection engaging the adjacent surface; the expansion cone is a radiallyexpandable tubular having a tapered end sliding into the seal sectionand a flared end for receiving the swage; and the swage is a tubularhaving a tapered end sliding into the expansion cone.
 3. The wellisolation apparatus according to claim 1, wherein the actuator includes:a sub connected to the sealing element; a compression sleevetransferring an axial loading on the expansion cone to the sub; a firstlocking member connecting the compression sleeve to the expansion cone;a second locking member connecting the compression sleeve to the sub; arelease sleeve having a first diameter configured to retain the firstlocking member in an engaged position with the expansion cone and areduced diameter neck; and a translating rod configured to shift therelease sleeve to slide the neck into engagement with the first lockingmember.
 4. A well isolation apparatus for use in a wellbore, comprising:a radially expandable sealing element configured to engage an interiorwall of a wellbore tubular; a radially expandable expansion cone intelescopic relationship with the sealing element, the expansion conebeing configured to expand the sealing element; and a swage configuredto telescopically engage and expand the expansion cone.
 5. The apparatusof claim 4, further comprising an actuator configured to sequentiallyengage the sealing element, the expansion cone, and the swage.
 6. Theapparatus of claim 5, further comprising a sub connected to the sealingelement, and wherein the actuator includes a compression sleeveconfigured to transfer an axial loading on the expansion cone to thesub.
 7. The apparatus of claim 6, further comprising a first lockingmember connecting the compression sleeve to the expansion cone, and asecond locking member connecting the compression sleeve to the sub. 8.The apparatus of claim 7, further comprising a release sleeve having afirst diameter configured to retain the first locking member in anengaged position with the expansion cone and a reduced diameter neck. 9.The apparatus of claim 8, further comprising a translating rodconfigured to shift the release sleeve to slide the neck into engagementwith the first locking member.
 10. A method for isolating a section of atubular in a wellbore, comprising: disposing an isolator, an actuator,and a setting tool in the tubular, wherein the isolator includes aswage, an expansion cone, and a sealing element in substantially serialalignment; sequentially engaging the swage, expansion cone, and thesealing element using the actuator; and activating the setting tool toaxially compress the isolator to concentrically align the swage, theexpansion cone, and the sealing element at a seal formed between thesealing element and an adjacent surface of the tubular.
 11. The methodof claim 10, further comprising removing the actuator and the settingtool from the wellbore.